Can a l5s1 herniation cause foot drop even though there is no clear cause showing on the mri? doc has said its snug but within norms. any suggestions?

Not likely: L5/s1 spinal nerve roots typically innervate the muscles to the bottom of side of the foot. To have foot drop usually entails weakness to the muscles to the top of the foot (ex, neurogenic, infectious, polio, etc). A herniation will not increase muscle strength to the bottom of the foot, so it's unlikely that herniation from l5/s1 will cause overpowering of bottom foot muscles.